1. _The straight cross cutting saw._--The log is placed horizontally on
a very low bench which is continued through the window of the mill into
the yard. The saw is exactly over the place where the log is to be
divided. It is let down, and suffered to rest with its teeth upon the
log, the back still being in the cleft of the guide. The crank being set
in motion, the saw reciprocates backwards and forwards with exactly the
same motion as if worked by a carpenter, and quickly cuts through the
tree. When it first begins to cut, its back is in the cleft in the
guide, and this causes it to move in a straight line; but before it gets
out of the guide, it is so deep in the wood as to guide itself: for in
cutting across the grain of the wood, it has no tendency to be diverted
from its true line by the irregular grain. When the saw has descended
through the tree, its handle is caught in a fixed stop, to prevent its
cutting the bench. The machine is thrown out of geer, the attendant
lifts up the saw by a rope, removes the block cut off, and advances the
tree to receive a fresh cut.
2. _The circular cross-cutting saw._--This saw possesses universal
motion; but the axis is always parallel to itself, and the saw in the
same plane. It can be readily raised or lowered, by inclining the upper
frame on its axis; and to move it sidewise, the saw frame must swing
sidewise on its joints, which connect it with the upper frame. These
movements are effected by two winches, each furnished with a pair of
equal pinions, working a pair of racks fixed upon two long poles. The
spindles of these winches are fixed in two vertical posts, which
support the axis of the upper frame. One of these pairs of poles is
jointed to the extreme end of the upper frame; therefore by turning the
handle belonging to them, the frame and saw is elevated or depressed; in
like manner, the other pair is attached to the lower part of the saw
frame, so that the saw can be moved sidewise by means of their handles,
which then swing the saw from its vertical position.
These two handles give the attendant a complete command of the saw,
which we suppose to be in rapid motion, the tree being brought forward
and properly fixed. By one handle, he draws the saw against one side of
the tree, which is thus cut into, (perhaps half through); now, by the
other handle, he raises the saw up, and by the first-mentioned handle he
draws it across the top of the tree, and cuts it half through from the
upper side; he then depresses the saw and cuts half through from the
next side; and lastly a trifling cut of the saw, at the lower side,
completely divides the tree, which is then advanced to take another cut.
_The great reciprocating saw_ is on the same principle as the saw mill
in common use in America.
3. _The circular ripping saw_ is a thin circular plate of steel, with
teeth similar to those of a pit saw, formed in its periphery. It is
fixed to a spindle placed horizontally, at a small distance beneath the
surface of a bench or table, so that the saw projects through a crevice
a few inches above the bench. The spindle being supported in proper
collars, has a rapid rotatory motion communicated to it by a pulley on
the opposite end, round which an endless strap is passed from a drum
placed overhead in the mill. The block cut by the preceding machine,
from the end of the tree, is placed with one of the sides flat upon the
bench, and thus slides forward against the revolving saw which cuts the
wood with a rapidity incredible to any one who has not seen these or
similar machines.
[Illustration: 131 132]
4. _Boring machine._--The blocks, prepared by the foregoing saws, are
placed in the machine represented in _fig._ 131. This machine has an
iron frame, A A, with three legs, beneath which the block is introduced,
and the screw near B being forced down upon it, confines it precisely in
the proper spot to receive the borers D and E. This spot is determined
by a piece of metal fixed perpendicularly just beneath the point of the
borer E, shown separately on the ground at X; this piece of metal
adjusts the position for the borer D, and its height is regulated by
resting on the head of the screw _x_, which fastens the piece X down to
the frame. The sides of the block are kept in a parallel position, by
being applied against the heads of three screws tapped into the double
leg of the frame A. The borer D is adapted to bore the hole for the
centre pin in a direction exactly perpendicular to the surface resting
against the three screws; the other, at E, perforates the holes for the
commencement of the sheave holes. Both borers are constructed in nearly
the same manner; they are screwed upon the ends of small mandrels,
mounted in frames similar to a lathe. These frames, G and H, are fitted
with sliders upon the angular edges of the flat broad bars, I and K. The
former of these is screwed fast to the frame; the latter is fixed upon a
frame of its own, moving on the centre screws, at L L, beneath the
principal frame of the machine. By this means the borer E can be moved
within certain limits, so as to bore holes in different positions. These
limits are determined by two screws, one of which is seen at _a_; the
other being on the opposite side is invisible. They are tapped through
fixed pieces projecting up from the frame. A projecting piece of metal,
from the under side of the slider K of the borer E, stops against the
ends of these screws, to limit the excursion of the borer. The frames
for both borers are brought up towards the block by means of levers M
and N. These are centered on a pin, at the opposite sides of the frame
of the machine, and have oblong grooves through them which receive screw
pins, fixed into the frames G and H, beneath the pulleys P P, which give
motion to the spindles.
5. _The mortising machine_ is a beautiful piece of mechanism, but too
complicated for description within the limits prescribed to this
article.
6. _The corner saw_, _fig._ 132., consists of a mandrel, mounted in a
frame A, and, carrying a circular saw L upon the extreme end of it. This
mandrel and its frame being exactly similar to those at G and H _fig._
131., does not require a separate view, although it is hid behind the
saw, except the end of the screw, marked A. This frame is screwed down
upon the frame B B of the machine, which is supported upon four columns.
C C, D D, is an inclined bench, or a kind of trough, in which a block is
laid, as at E, being supported on its edge by the plane C C of this
bench, and its end kept up to its position by the other part of the
bench D D.
By sliding the block along this bench, it is applied to the saw, which
cuts off its angles, as is evident from the figure, and prepares it for
the shaping engine. All the four angles are cut off in succession, by
applying its different sides to the trough or bench. In the figure, two
of them are drawn as being cut, and the third is just marked by the saw.
This machine is readily adapted to different sizes of blocks, by the
simple expedient of laying pieces of wood of different thickness against
the plane D D, so as to fill it up, and keep the block nearer to or
farther from the saw; for all the blocks are required to be cut at the
same angle, though, of course, a larger piece is to be cut from large
than from small blocks. The block reduced to the state of E is now taken
to
7. _The shaping machine._--A great deal of the apparent complication of
this figure arises from the iron cage, which is provided to defend the
workmen, lest the blocks, which are revolving in the circles, or chuck,
with an immense velocity, should be loosened by the action of the tool,
and fly out by their centrifugal force. Without this provision, the
consequences of such an accident would be dreadful, as the blocks would
be projected in all directions, with an inconceivable force.
8. _The scoring engine_ receives two blocks, as they come from the
shaping engine, and forms the groove round their longest diameters for
the reception of their ropes or straps, as represented in the two snatch
blocks and double block, under _figs._ 131, 132.
[Illustration: 133]
A, B, _fig._ 133., represent the above two blocks, each held between two
small pillars _a_, (the other pillar is hid behind the block) fixed in a
strong plate D, and pressed against the pillars by a screw _b_, which
acts on a clamp _d_. Over the blocks a pair of circular planes or
cutters E E, are situated, both being fixed on the same spindle, which
is turned by a pulley in the middle of it. The spindle is fitted in a
frame F F, moving in centres at _e e_, so as to rise and fall when
moved by a handle _f_. This brings the cutters down upon the blocks; and
the depth to which they can cut is regulated by a curved shape _g_,
fixed by screws upon the plate D, between the blocks. Upon this rests a
curved piece of metal _h_, fixed to the frame F, and inclosing, but not
touching, the pulley. To admit the cutters to traverse the whole length
of the blocks, the plate D, (or rather a frame beneath it,) is sustained
between the points of two centres. Screws are seen at _l_, on these
centres. The frame inclines when the handle L is depressed. At M is a
lever, with a weight at the end of it, counterbalancing the weight of
the blocks, and plate D, all which are above the centre on which they
move. The frame F is also provided with a counterpoise to balance the
cutters, &c. The cutters E E are circular wheels of brass, with round
edges. Each has two notches in its circumference, at opposite sides; and
in these notches chisels are fixed by screws, to project beyond the rim
of the wheel, in the manner of a plane iron before its face.
This machine is used as follows:--In order to fix the block, it is
pressed between the two pins (only one of which at _a_, can be seen in
this view), and the clamp _d_, screwed up against it, so as just to hold
the block, but no more. The clamp has two claws, as is seen in the
figure, each furnished with a ring entering the double prints previously
made, in the end of the block. These rings are partly cut away, leaving
only such a segment of each as will just retain the block, and the metal
between them is taken out to admit the cutter to operate between them,
or nearly so. In putting the blocks into this machine, the workman
applies the double prints to the ends of the claws of the clamps, but
takes care that the blocks are higher between the pins _a_ than they
should be; he then takes the handle _f_, and by it presses the cutters E
E, (which we suppose are standing still,) down upon the blocks,
depressing them between their pins at the same time, till the descent of
the cutters is stopped by the piece _h_ resting on the shape _g_. He now
turns the screws _b b_, to fix the blocks tight. The cutters being put
in motion cut the scores, which will be plainly seen by the mode of
adjustment just described, to be of no depth at the pin-hole; but by
depressing the handle L, so as to incline the blocks, and keeping the
cutters down upon their shape _g_, by the handle _f_, they will cut any
depth towards the ends of the blocks, which the shape _g_ admits.
By this means one quarter of the score is formed; the other is done by
turning both blocks together half round in this manner. The centres _l_
are not fitted into the plate D itself, but into a frame seen at R
beneath the plate, which is connected with it by a centre pin, exactly
midway between the two blocks A B. A spring catch, the end of which is
seen at _r_, confines them together; when this catch is pressed back,
the plate D can be turned about upon its centre pin, so as to change the
blocks, end for end, and bring the unscored quarters (_i. e._ over the
clamps) beneath the cutters; the workman taking the handles _f_ and L,
one in each hand, and pressing them down, cuts out the second quarter.
This might have been effected by simply lifting up the handle L; but in
that case the cutter would have struck against the grain of the wood, so
as to cut rather roughly; but by this ingenious device of reversing the
blocks, it always cuts clean and smooth, in the direction of the grain.
The third and fourth quarters of the score are cut by turning the other
sides of the blocks upwards, and repeating the above operation. The
shape _g_ can be removed, and another put in its place, for different
sizes and curves of block; but the same pins _a_, and holding clamps
_d_, will suit many different sizes.
By these machines the shells of the blocks are completely formed, and
they are next polished and finished by hand labour; but as this is
performed by tools and methods which are well known, it is needless to
enter into any explanation: the finishing required being only a
smoothing of the surfaces. The machines cut so perfectly true as to
require no wood to be removed in the finishing; but as they cut without
regard to the irregularity of the grain, knots, &c., it happens that
many parts are not so smooth as might be wished, and for this purpose
manual labour alone can be employed.
The lignum vitæ for the sheaves of the blocks, is cut across the grain
of the wood by two cross cutting saws, a circular and straight saw, as
before mentioned. These machines do not essentially differ in their
principle from the great cross cutting saws we have described, except
that the wood revolves while it is cutting, so that a small saw will
reach the centre of a large tree, and at the same time cut it truly
flat. The limits prescribed for our plates will not admit of giving
drawings of these machines, and the idea which could be derived from a
verbal description would not be materially different from the cross
cutting saws before mentioned. These machines cut off their plates for
the end of the tree, which are exactly the thickness for the intended
sheave. These pieces are of an irregular figure, and must be rounded and
centered in the crown saw.
[Illustration: 134]
9. _The crown saw_ is represented in _fig._ 134., where A is a pulley
revolving by means of an endless strap. It has the crown or trepan saw
_a_ fixed to it, by a screw cut within the piece, upon which the saw is
fixed, and which gives the ring or hoop of the saw sufficient stability
to perform its office. Both the pulleys and saw revolve together upon a
truly cylindrical tube _b_, which is stationary, being attached by a
flaunch _c_ to a fixed puppet B, and on this tube as an axis the saw and
pulley turn, and may be slid endwise by a collar fitted round the centre
piece of the pulley, and having two iron rods (only one of which can be
seen at _d_ in the figure), passing through holes made through the
flaunch and puppet B. When the saw is drawn back upon its central tube,
the end of the latter projects beyond the teeth of the saw. It is by
means of this fixed ring or tube within the saw, that the piece of wood
_e_ is supported during the operation of sawing, being pressed forcibly
against it by a screw D, acting through a puppet fixed to the frame of
the machine. At the end of this screw is a cup or bason which applies
itself to the piece of wood, so as to form a kind of vice, one side
being the end of the fixed tube, the other the cup at the end of the
screw D. Within the tube _b_ is a collar for supporting a central axis,
which is perfectly cylindrical. The other end of this axis, (seen at
_f_,) turns in a collar of the fixed puppet E. The central axis has a
pulley F, fixed on it, and giving it motion by a strap similar to the
other. Close to the latter pulley a collar _g_ is fitted on the centre
piece of the pulley, so as to slip round freely, but at the same time
confined to move endways with the pulley and its collar. This collar
receives the ends of the two iron rods _d_. The opposite ends of these
rods are, as above mentioned, connected by a similar collar, with the
pulley A of the saw _a_. By this connection, both the centre bit, which
is screwed into the end of the central axis _f_, and the saw sliding
upon the fixed tube _b_, are brought forward to the wood at the same
time, both being in rapid motion by their respective pulleys.
10. _The Coaking Engine._--This ingenious piece of machinery is used to
cut the three semicircular holes which surround the hole bored by the
crown saw, so as to produce a cavity in the centre of the disc.
11. _Face-turning Lathe._--The sheave is fixed against a flat chuck at
the end of a mandrel, by an universal chuck, similar to that in the
coaking engine, except that the centre pin, instead of having a nut, is
tapped into the flat chuck, and turned by a screw-driver.
BLOOD. (_Sang_, Fr.; _Blut_, Germ.) The liquid which circulates in the
arteries and veins of animals; bright red in the former and purple in
the latter, among all the tribes whose temperature is considerably
higher than that of the atmosphere. It consists 1. of a colourless
transparent solution of several substances in water; and 2. of red,
undissolved particles diffused through that solution. Its specific
gravity varies with the nature and health of the animal; being from
1·0527 to 1·0570 at 60° F. It has a saline sub-nauseous taste, and a
smell peculiar to each animal. When fresh drawn from the vessels, it
rapidly coagulates into a gelatinous mass, called the clot, cruor, or
crassamentum, from which after some time, a pale yellow fluid, passing
into yellowish green, oozes forth, called the _serum_. If the warm blood
be stirred with a bundle of twigs, as it flows from the veins, the
fibrine concretes, and forms long fibres and knots, while it retains its
usual appearance in other respects. The clot contains fibrine and
colouring matter in various proportions. Berzelius found in 100 parts of
the dried clot of blood, 35 parts of fibrine, 58 of colouring matter;
1·3 of carbonate of soda; 4 of an animal matter soluble in water, along
with some salts and fat. The specific gravity of the serum varies from
1·027 to 1·029. It forms about three fourths of the weight of the blood,
has an alkaline reaction, coagulates at 167° F. into a gelatinous mass,
and has for its leading constituent _albumen_ to the amount of 8 per
cent. besides fat, potash, soda, and salts of these bases. Blood does
not seem to contain any gelatine.
The red colouring matter called _hematine_, may be obtained from the
cruor by washing with cold water and filtering.
Blood was at one time largely employed for clarifying syrup, but it is
very sparingly used by the sugar refiners in Great Britain of the
present day. It may be dried by evaporation at a heat of 130° or 140°,
and in this state has been transported to the colonies for purifying
cane juice. It is an ingredient in certain adhesive cements, coarse
pigments for protecting walls from the weather, for making animal
charcoal in the Prussian blue works, and by an after process, a
decolouring carbon. It is used in some Turkey red dye-works. Blood is a
powerful manure.
BLOWING MACHINE. See IRON, METALLURGY, VENTILATION.
BLOWPIPE. (_Chalumeau_, Fr.; _Lothröhre_, Germ.) Jewellers,
mineralogists, chemists, enamellers, &c. make frequent use of a tube,
usually bent near the end, terminated with a finely pointed nozzle, for
blowing through the flame of a lamp, candle, or gas-jet, and producing
thereby a small conical flame possessing a very intense heat.
Modifications of blow pipes are made with jets of hydrogen, oxygen, or
the two gases mixed in due proportions.
BLUE DYES. (_Teint_, Germ. See ENAMEL.) The materials employed for this
purpose are indigo, Prussian blue, logwood, bilberry, (_vaccinium
myrtillus_,) elder berries, (_sambucus nigra_,) mulberries, privet
berries, (_ligustrum vulgare_,) and some other berries whose juice
becomes blue by the addition of a small portion of alkali, or of the
salts of copper. For dyeing with the first three articles, see them in
their alphabetical places. I shall here describe the other or minor blue
dyes.
To dye blue with such berries as the above, we boil one pound of them in
water, adding one ounce of alum, of copperas, and of blue vitriol, to
the decoction, or in their stead equal parts of verdegris and tartar,
and pass the stuffs a sufficient time through the liquor. When an iron
mordant alone is employed, a steel blue tint is obtained; and when a tin
one, a blue with a violet cast. The privet berries which have been
employed as sap colours by the card painters, may be extensively used in
the dyeing of silk. The berries of the African night-shade (_solanum
guineense_) have been of late years considerably applied to silk on the
continent in producing various shades of blue, violet, red, brown, &c.
but particularly violet. With alkalis and acids these berries have the
same habitudes as bilberries; the former turning them green, the latter
red. They usually come from Italy compressed in a dry cake, and are
infused in hot water. The infusion is merely filtered, and then employed
without any mordant, for dyeing silk, being kept at a warm temperature
by surrounding the bath vessel with hot water. The goods must be winced
for six hours through it in order to be saturated with colour; then they
are to be rinsed in running water and dried. One pound of silk requires
a pound and a half of the berry cake. In the residuary bath, other tints
of blue may be given. Sometimes the dyed silk is finished by running it
through a weak alum water. A colour approaching to indigo in permanence,
but which differs from it in being soluble in alkalis, though incapable
of similar disoxidizement, is the _gardenia genipa_ and _aculeata_ of
South America whose colourless juice becomes dark blue with contact of
air; and dyes stuffs, the skin, and nails, of an unchangeable deep blue
colour, but the juice must be applied in the colourless state.
BLUE PIGMENTS. Several metallic compounds possess a blue colour;
especially those of iron, cobalt, and molybdenum. The metallic pigments,
little if at all employed, but which may be found useful in particular
cases, are the molybdate of mercury, the hydro-sulphuret of tungsten,
the prussiate of tungsten, the molybdate of tin, the oxide of copper
darkened with ammonia, the silicate of copper, and a fine violet colour
formed from manganese and molybdenum. The blues of vegetable origin, in
common use, are indigo, litmus, and blue cakes. The blue pigments of a
metallic nature found in commerce are the following: _Prussian blue_;
_mountain blue_, a carbonate of copper mixed with more or less earthy
matter; _Bremen blue_, or _verditer_, a greenish blue colour obtained
from copper mixed with chalk or lime; _iron blue_, phosphate of iron,
little employed; _cobalt blue_, a colour obtained by calcining a salt of
cobalt with alumina or oxide of tin; _smalt_, a glass coloured with
cobalt and ground to a fine powder; _charcoal blue_, a deep shade
obtained by triturating carbonized vine stalks with an equal weight of
potash in a crucible till the mixture ceases to swell, then pouring it
upon a slab, putting it into water and saturating the alkali with
sulphuric acid. The liquor becomes blue, and lets fall a dark blue
precipitate, which becomes of a brilliant blue colour when heated.
Molybdenum blue is a combination of this metal, and oxide of tin or
phosphate of lime. It is employed both as a paint, and an enamel colour.
A blue may also be obtained by putting into molybdic acid, (made by
digesting sulphuret of molybdenum with nitric acid,) some filings of
tin, and a little muriatic acid. The tin deoxidizes the molybdic acid to
a certain degree, and converts it into the molybdous, which when
evaporated and heated with alumina recently precipitated, forms this
blue pigment. _Ultramarine_ is a beautiful blue pigment, which see.
BLUE VITRIOL; sulphate of copper.
BOMBAZINE. A worsted stuff, sometimes mixed with silk.
BONES. (_Os_, Fr.; _Knochen_, Germ.) They form the frame work of animal
bodies, commonly called the skeleton; upon which the soft parts are
suspended, or in which they are enclosed. Bones are invested with a
membrane styled the periosteum, which is composed of a dense tissue
affording glue; whence it is convertible into jelly, by ebullition with
water. Bones are not equally compact throughout their whole substance;
the long ones have tubes in their centres lined with a kind of
periosteum, of more importance to the life of the bones than even their
external coat. The flat, as well as the short and thick bones, exhibit
upon their surface an osseous mass of a dense nature, while their
interior presents a cavity divided into small cellules by their bony
partitions.
In reference to the composition of bones, we have to consider two
principal constituents; the living portion or the osseous cartilage, and
the inorganic or the earthy salts of the bones.
The osseous cartilage is obtained by suspending bones in a large vessel
full of dilute muriatic acid, and leaving it in a cool place at about
50° Fahr. for example. The acid dissolves the earthy salts of the bones
without perceptibly attacking the cartilage, which, at the end of a
short time, becomes soft and translucid, retaining the shape of the
bones; whenever the acid is saturated, before it has dissolved all the
earthy salts it should be renewed. The cartilage is to be next suspended
in cold water, which is to be frequently changed till it has removed all
the acidity. By drying, the cartilage shrinks a little, and assumes a
darker hue, but without losing its translucency. It becomes, at the same
time, hard and susceptible of breaking when bent, but it possesses great
strength.
This cartilage is composed entirely of a tissue passing into gelatine.
By boiling with water, it is very readily convertible into a glue, which
passes clear and colourless through the filter, leaving only a small
portion of fibrous matter insoluble by further boiling. This matter is
produced by the vessels which penetrate the cartilage, and carry
nourishment to the bone. We may observe all these phenomena in a very
instructive manner, by macerating a bone in dilute muriatic acid, till
it has lost about the half of its salts; then washing it with cold
water, next pouring boiling water upon it, leaving the whole in repose
for 24 hours, at a temperature a few degrees below 212° Fahr.
The cartilage, which has been stripped of its earthy salts dissolves,
but the small vessels which issue from the undecomposed portion of the
bone remain under the form of white plumes, if the water has received no
movement capable of crushing or breaking them. We may then easily
recognise them with a lens, but the slightest touch tears them, and
makes them fall to the bottom of the vessel in the form of a
precipitate; if we digest bones with strong hot muriatic acid so as to
accelerate their decomposition, a portion of the cartilage dissolves in
the acid with a manifest disengagement of carbonic acid gas, which
breaks the interior mass, and causes the half-softened bone to begin to
split into fibrous plates, separable in the direction of their length.
According to Marx these plates, when sufficiently thin, possess, like
scales of mica, the property of polarising light, a phenomenon which
becomes more beautiful still when we soak them with the essential oil of
the bark of the Laurus Cassia. The osseous cartilage is formed before
the earthy part. The long bones are then solid, and they become hollow
only in proportion as the earthy salts appear. In the new-born infant, a
large portion of the bones is but partially filled with these salts,
their deposition in cartilage takes place under certain invariable
_points of ossification_, and begins at a certain period after
conception, so that we may calculate the age of the foetus according to
the progress which ossification has made.
The earthy parts of bones are composed principally of the phosphate and
carbonate of lime in various proportions, variable in different animals,
and mixed with small quantities, equally variable, of phosphate of
magnesia and fluate of lime. The easiest means of procuring the earthy
salts of bones consists in burning them to whiteness, but the earthy
residuum procured in this manner, contains substances which did not
exist beforehand in the bones, and which did not form a part of their
earthy salts; as for example sulphate of soda, produced at the expense
of the sulphur of the bones and the alkaline carbonate, proceeding from
the cartilage with which it was combined. On the other hand, the greater
part of the lime has lost its carbonic acid. As the sulphuric acid is
the product of combustion, it is obvious that an acidulous solution of a
fresh bone can afford no precipitate with muriate of barytes. The
phosphate of lime contained in the bone-salts is a subphosphate,
consisting, according to Berzelius, of three prime equivalents of the
acid, and 8 of the base; or of 2,677 parts of the former, and 2,848 of
the latter. It is always obtained when we precipitate the phosphate of
lime by an excess of ammonia. When calcined bones are distilled in a
retort with their own weight of sulphuric acid, a little fluoric acid is
disengaged, and it acts on the surface of the glass. The following
analyses of the bones of men and horned cattle, are given by Berzelius.
They were dried after being stripped of their fat and periosteum till
they lost no more weight.
+-----------------------------------------+-----------+--------+
| |Human bone.|Ox bone.|
+-----------------------------------------+-----------+--------+
|Cartilage completely soluble in water | 32·17 } | 33·3 |
|Vessels | 1·13 } | |
|Subphosphate with a little fluate of lime| 53·04 | 57·35 |
|Carbonate of lime | 11·3 | 3·85 |
|Phosphate of magnesia | 1·16 | 2·05 |
|Soda with very little muriate of soda | 1·20 | 3·45 |
| | ------ | ------ |
| | 100·00 | 100·00 |
+-----------------------------------------+-----------+--------+
The most essential difference in the composition of these bones is that
those of man contain three times as much carbonate of lime as those of
the ox; and that the latter are richer in phosphate of lime and magnesia
in the same proportion. Fernandez de Barros has established a comparison
between the phosphate and carbonate of lime in the bones of different
animals. He found in 100 parts of earthy salt of the bones of the
following animals:--
+-----+------------------+-----------+
| |Phosphate of lime.|Carb. lime.|
+-----+------------------+-----------+
|Lion | 95·0 | 2·5 |
|Sheep| 80·0 | 19·3 |
|Hen | 88·9 | 10·4 |
|Frog | 95·2 | 2·4 |
|Fish | 91·9 | 5·3 |
+-----+------------------+-----------+
The bones of fish are divided into those which contain earthy salts and
those which have none, called cartilaginous fishes. The enamel of the
teeth is composed as follows:--
+-------------------------------------+-------------+----------+
| |Human enamel.|Ox enamel.|
+-------------------------------------+-------------+----------+
|Phosphate of lime with fluate of lime| 88·5 | 85·0 |
|Carbonate of lime | 8·0 | 7·1 |
|Phosphate of magnesia | 1·5 | 3·0 |
|Soda | 0·0 | 1·4 |
|Brown membranes attached to the tooth| 2·0 | 3·5 |
|alkali, water | | |
| | ----- | ----- |
| | 100·0 | 100·0 |
+-------------------------------------+-------------+----------+
In the arts, the bones are employed by turners, cutlers, manufacturers
of animal charcoal; and, when calcined, by assayers for making cupels.
In agriculture, they are employed as a manure, for which purpose they
should be ground in a mill, and the powder sowed along with the seeds in
a drill. It is supposed, in many cases, to increase the crop in weight
of grain and straw together, by from 40 to 50 per cent. In France, soup
is extensively made by dissolving bones in a steam-heat of two or three
days’ continuance. The shavings of hartshorn, which is a species of
bone, afford an elegant jelly: the shavings of calves’ bones may be used
in their stead.
Living bones acquire a red tinge when the animals receive madder with
their food; but they lose it when the madder is discontinued for some
time.
BONE BLACK (_Noir d’os_, Fr.; _Knochenschwartz_, Germ.), or _Animal
charcoal_, as it is less correctly called, is the black carbonaceous
substance into which bones are converted by calcination in close
vessels. This kind of charcoal has two principal applications; to
deprive various solutions, particularly syrups, of their colouring
matters, and to furnish a black pigment. The latter subject will be
treated of under IVORY BLACK.
The discovery of the antiputrescent and decolouring properties of
charcoal in general, is due to Lowitz, of Petersburg; but their
modifications have occupied the attention of many chemists since his
time. Kels published, in 1798, some essays on the discolouring of
indigo, saffron, madder, syrup, &c. by means of charcoal, but he
committed a mistake in supposing bone black to have less power than the
charcoal of wood. The first useful application of charcoal to the
purification of raw colonial sugar was made by M. Guillon, who brought
into the French markets considerable quantities of fine syrups, which he
discoloured by ground wood charcoal, and sold them to great advantage,
as much superior to the cassonades of that time. In 1811, M. Figuier, an
apothecary at Montpellier, published a note about animal charcoal,
showing that it blanched vinegars and wines with much more energy than
vegetable charcoal; and, lastly, in 1812, M. Derosnes proposed to
employ animal charcoal in the purification of syrups and sugar refining.
The quantities of bone black left in the retorts employed by MM. Payen,
for producing crude carbonate of ammonia, furnished abundant materials
for making the most satisfactory experiments, and enabled these
gentlemen soon to obtain ten per cent. more of refined sugar from the
raw article than had been formerly extracted, and to improve, at the
same time, the characters of the lumps, bastards, treacle, &c.
[Illustration: 135 136 137 138]
The calcination of bones is effected by two different systems of
apparatus; by heating them in a retort similar to that in which coal is
decomposed in the gas works, or in small pots piled up in a kiln. For
the description of the former, see GAS-LIGHT. On the second plan, the
bones, broken into pieces, are put into small cast-iron pots of the form
shown in _fig._ 135., about three eighths of an inch thick, two of which
are dexterously placed with their mouths in contact, and then luted
together with loam. The lip of the upper pot is made to slip inside of
the under one. These double vessels, containing together about fifty
pounds of bones, are arranged alongside, and over each other, in an
oven, like a potter’s kiln, till it be filled. The oven or kiln may be
either oblong or upright. The latter is represented in _fig._ 136, 137,
138. A is the fireplace or grate for the fuel; C C are the openings in
the dome of the furnace through which the flame flows; the divisions of
these orifices are shown in _fig._ 138. B is the wall of brick-work. D
the space in which the pots are distributed. E is the door by which the
workman carries in the pots, which is afterwards built up with fire
bricks, and plastered over with loam. This door is seen in _fig._ 136. F
F are the lateral flues for conveying the disengaged gases into the air.
[Illustration: 139 140]
_Fig._ 139. is a longitudinal section, and _fig._ 140. a ground plan of
a horizontal kiln for calcining bones. _a_ is the fire-chamber, lying
upon a level with the sole of the kiln; it is separated by a pillar _b_,
from the calcining hearth _c_. In the pillar or wall, several rows of
holes _d_, are left at different heights; _e_ is the entrance door; _f_,
the outlet vents for the gases, vapours, and smoke, into the chimney
_g_; _h_, a sliding damper-plate for regulating the admission of the air
into the fire in the space _a_.
By this arrangement the offensive emanations are partly consumed, and
partly carried off with the smoke. To destroy the smell completely, the
smoke should be made to pass through a second small furnace.
The number of pots that may be put into a kiln of this kind depends, of
course, upon its dimensions; but, in general, from 100 to 150 are piled
up over each other, in columns, at once; the greatest heat being nearest
the roof of the kiln; which resembles, in many respects, that used for
baking pottery ware.
In both kilns the interior walls are built of fire-bricks. In the oblong
one, the fiercest heat is near the vaulted roof; in the upright one,
near the sole; and the pots, containing the larger lumps of bones,
should be placed accordingly near the top of the former, and the bottom
of the latter. Such a kiln may receive about seventy double pots,
containing in the whole thirty-five cwt. of bones.
After the earth is filled with the pots, and the entrance door is shut,
the fire is applied at first moderately, but afterwards it must be
raised and maintained, at a brisk heat, for eight or ten hours. The door
of the ash-pit and the damper may now be nearly closed, to moderate the
draught, and to keep up a steady ignition for six or eight hours longer,
without additional firing; after which the doors must be all opened to
cool the furnace. When this is done, the brick-work of the entrance door
must be taken down, the kiln must be emptied, and immediately filled
again with a set of pots previously filled with bones, and luted
together: the pots which have been ignited may, in the course of a short
time, be opened, and the contents put into the magazine. But in
operating with the large decomposing cylinder retort, the bones being
raked out hot, must be instantly tossed into a receiver, which can be
covered-in air-tight till they are cool.
The bones lose upon the average about one half of their weight in the
calcination. In reference to the quality of the black, experience has
shown that it is so much more powerful as a discolouring agent, as the
bones from which it was made have been freer from adhering fatty,
fleshy, and tendinous matters.
The charcoal is ground in a mill, either to a fine powder and sifted; or
into a coarse granular state, like gunpowder, for the preparation of
which two sieves are required, one with moderately fine meshes, to allow
the small dust to pass through, and one with large meshes, to separate
the proper sized grains from the coarser lumps. Either a corn-mill, an
edgestone mill, or a steel cylinder mill, may be employed for grinding
bone-black, and it is generally damped in the operation to keep down the
fine dust.
Bone-black, as found in commerce, is very variable in its discolouring
power, which arises from its having been exposed either to too great a
heat which has glazed its carbon, or to too low a heat which has left
its albumen imperfectly decomposed. A steady ignition of due continuance
is the proper decomposing temperature. Its composition is generally as
follows:--
Phosphate of lime, with carbonate of lime, and a little sulphuret of
iron, or oxide of iron, 88 parts; iron in the state of a silicated
carburet, 2 parts; charcoal containing about one fifteenth of azote, 10
parts. None of the substances present, except the charcoal, possesses
separately any discolouring power.
The quality may be tested by a solution of brown sugar, or molasses, or
of indigo in sulphuric acid. The last is generally preferred by the
French chemists, who have occupied themselves most with this subject,
and it contains usually one thousandth part of its weight of this
dye-drug of the best quality. Other animal substances yield a charcoal,
possessed of very considerable discolouring properties. The following
table by M. Bussy exhibits an interesting comparison of almost every
kind of charcoal in this point of view.
Table of the discolouring powers of different charcoals.
+--------------------------+-------+-------+--------+--------+------+
| | |Indigo |Molasses|Blanch- |Power |
|Species of Charcoal. |Weight.| test | test |ing by | by |
| | con- | con- |indigo. |molas-|
| | |sumed. | sumed. | |ses. |
+--------------------------+-------+-------+--------+--------+------+
| |Gramme.|Litres.| | | |
|Blood calcined with potash| 1 | 1·60 | 0·18 | 50 | 20 |
|Ditto with chalk | 1 | 0·57 | 0·10 | 18 | 11 |
|Ditto with phosp. lime | 1 | 0·38 | 0·09 | 12 | 10 |
|Gelatine ditto with potash| 1 | 1·15 | 0·14 | 36 | 15·5 |
|Albumen ditto ditto | 1 | 1·08 | 0·14 | 34 | 15·5 |
|Starch ditto ditto | 1 | 0·34 | 0·08 | 10·6 | 8·8 |
|Charcoal from acet. potash| 1 | 0·18 | 0·04 | 5·6 | 4·4 |
|Ditto from carb. soda by | 1 | 0·38 | 0·08 | 12 | 8·8 |
|phosphorus | | | | | |
|Calcined lamp black | 1 | 0·128 | 0·03 | 4 | 3·3 |
|Ditto ditto potash | 1 | 0·55 | 0·09 | 15·2 | 10·6 |
|Bone black treated with | 1 | 1·45 | 0·18 | 45 | 20 |
|mur. acid and potash | | | | | |
|Bone black ditto with mur.| 1 | 0·06 | 0·015 | 1·87 | 1·6 |
|acid | | | | | |
|Oil calcined with phosp. | 1 | 0·064 | 0·017 | 2 | 1·9 |
|of lime | | | | | |
|Crude bone black | 1 | 0·032 | 0·009 | 1 | 1 |
+--------------------------+-------+-------+--------+--------+------+
With regard to the mode of operation of bone black on coloured liquids,
M. Payen showed in his prize essay, 1. That the decolouring power of
charcoal depends in general upon its state of division; 2. That in the
various charcoals, the carbonaceous matter acts only upon the colouring
matters, combining with and precipitating them; 3. That in the
application of charcoal to the refining of sugar, it acts also upon the
gluten, for it singularly promotes crystallisation; 4. That according to
the above principles, the decolouring action of charcoals may be so
modified, as to make the most inert become the most active; 5. That the
distinction between animal and vegetable charcoals is improper, and that
we may substitute for it that of dull and brilliant charcoals; 6. That
of the substances present in charcoal besides carbon, and particularly
animal charcoal, those which favour the decolouring action, have an
influence relative only to the carbon; they serve as auxiliaries to it,
by insulating its particles, and presenting them more freely to the
action of the colouring matter; 7. That animal charcoal, besides its
decolouring power, has the valuable property of taking lime in solution
from water and syrup; 8. That neither vegetable, nor other charcoals,
besides the animal, have this power of abstracting lime; 9. That by the
aid of the decolorimeter, or graduated tube charged with test solution
of indigo or molasses, it is easy to appreciate exactly the decolouring
properties of all kinds of charcoal.
Different varieties of lignite (fossilized wood) or even pit coal, when
well carbonized in close vessels, afford a decolouring charcoal of
considerable value. By reducing 100 parts of clay into a thin paste with
water, kneading into it 20 parts of tar, and 500 of finely ground pit
coal, drying the mixed mass, and calcining it out of contact of air, a
charcoally matter may be obtained not much inferior to bone-black in
whitening syrups.
The restoration of animal charcoal from burnt bones, for the purpose of
sugar refining, has been long practised in France. Mr. W. Parker has
lately made the following process the subject of a patent. The charcoal,
when taken from the vessels in which it has been employed for the
purposes of clarifying the sugar, is to be thoroughly washed with the
purest water that can be obtained, in order to remove all the saccharine
matter adhering to it. When the washing process has been completed, the
charcoal is laid out to dry, either in the open air or in a suitable
stove, and when perfectly free from moisture, it is to be separated into
small pieces and sifted through a sieve, the wires or meshes of which
are placed at distances of about two and a half in every inch. This
sifting will not only divide the charcoal into small pieces, but will
cause any bits of wood or other improper matters to be separated from
it.
The charcoal, thus prepared, is then to be packed lightly in cylindrical
vessels called crucibles, with some small quantity of bones, oil, or
other animal matter mixed with it. The crucibles are then to be closed
by covers, and luted at the joints, leaving no other opening but one
small hole in the centre of the cover, through which any gas, generated
within the vessel when placed in the oven or furnace, may be allowed to
escape.
The crucibles are now to be ranged round the oven, and placed, one upon
another, in vertical positions; and when the oven is properly heated,
gas will be generated within each crucible, and issue out from the
central hole. The gas thus emitted, being of an inflammable quality,
will take fire, and assist in heating the crucibles; and the operation
being carried on until the crucibles become of a red heat, the oven is
then to be closed, and allowed to cool; after which the crucibles are to
be removed, when the charcoal will be found to have become perfectly
renovated, and fit for use as before.
BORAX. A native saline compound of boracic acid and soda, found
abundantly in Thibet and in South America. The crude product from the
former locality was imported into Europe under the name of _tincal_, and
was purified from some adhering fatty matter by a process kept a long
time secret by the Venetians and the Dutch, and which consisted chiefly
in boiling the substance in water with a little quicklime.
Gmelin found borax, in prismatic crystals, to contain 46·6 per cent. of
water; and Arvredson, in the calcined state, to consist of 68·9 of acid
and 31·1 soda, in 100 parts. M. Payen describes an octahedral borax,
which contains only 30·64 per cent. of water, and is therefore preferred
by the braziers in their soldering processes.
Borax has a sweetish, somewhat lixivial taste, and affects vegetable
colours like an alkali; it is soluble in 12 parts of cold and 2 of
boiling water. It effloresces and becomes opaque in a dry atmosphere,
and appears luminous, by friction, in the dark. It melts at a heat a
little above that of boiling water, and gives out its water of
crystallization, after which it forms a spongy mass, called calcined
borax. The octahedral borax, which is prepared by crystallization, in a
solution of 1·256 sp. gr., kept up at 145° F., is not efflorescent. When
borax is ignited, it fuses into a glassy-looking substance.
The following is the improved mode of purifying borax. The crude
crystals are to be broken into small lumps, and spread upon a filter
lined with a lead grating, under which a piece of cloth is stretched
upon a wooden frame. The lumps are piled up to the height of 12 inches,
and washed with small quantities of a caustic soda lye of 5° B. (sp. gr.
1·033) until the liquor comes off nearly colourless; they are then
drained, and put into a large copper of boiling water, in such
quantities that the resulting solution stands 20° B. (sp. gr. 1·160).
Carbonate of soda, equivalent to 12 per cent. of the borax must now be
added; the mixed solution is allowed to settle, and the clear liquid
syphoned off into crystallizing vessels. Whenever the mother waters get
foul, they must be evaporated to dryness in cast-iron pots, and roasted,
to burn away the viscid colouring matter.
Borax is sometimes adulterated with alum and common salt: the former
addition may be readily detected by a few drops of water of ammonia,
which will throw down its alumina; and the latter by nitrate of silver,
which will give with it a precipitate insoluble in nitric acid.
The native boracic acid obtained from the lakes of Tuscany, which has
been manufactured in France into borax, has greatly lowered the price of
this article of commerce. When MM. Payen and Cartier first began the
business, they sold the crystals at the same price as the Dutch, viz. 7
francs the kilogramme (2-1/5 lbs. avoird.); but, in a few years, they
could obtain only 2 francs and 60 centimes, in consequence of the market
getting overstocked. The annual consumption of France in 1823 was 25,000
kilos., and the quantity produced in M. Payen’s works was 50,000. The
mode of making borax from the acid is as follows:--The lake water is
evaporated in graduation houses, and then concentrated in boilers till
it crystallizes. In that state it is carried to Marseilles. About 500
kilogrammes of water are made to boil in a copper, and 600 kilogrammes
of crystallized carbonate of soda are dissolved in it by successive
additions of 20 kilogrammes. The solution being maintained at nearly the
boiling point, 500 kilogrammes of the crystallized boracic acid of
Tuscany are introduced, in successive portions. At each addition of
about 10 kilogrammes, a lively effervescence ensues, on which account
the copper should be of much greater capacity than is sufficient to
contain the liquors. When the whole acid has been added, the fire must
be damped by being covered up with moist ashes, and the copper must be
covered with a tight lid and blankets, to preserve the temperature
uniform. The whole is left in this state during 30 hours; the clear
liquor is then drawn off into shallow crystallizing vessels of lead, in
which it should stand no higher than 10 or 12 inches, to favour its
rapid cooling. At the end of three days in winter, and four in summer,
the crystallization is usually finished. The mother water is drawn off,
and employed, instead of simple water, for the purpose of dissolving
fresh crystals of soda. The above crystals are carefully detached with
chisels, redissolved in boiling water, adding for each 100 kilos., 10
kilos. of carbonate of soda. This solution marks 20° B. (sp. gr. 1·160);
and, at least, one ton (1000 kilos.) of borax should be dissolved at
once, in order to obtain crystals of a marketable size. Whenever this
solution has become boiling hot, it must be run off into large
crystallizing lead chests of the form of inverted truncated pyramids,
furnished with lids, enclosed in wooden frames, and surrounded with mats
to confine the heat. For a continuous business there should be at least
18 vessels of this kind; as the solution takes a long time to complete
its crystallization, by cooling to 30° C. (86° F.). The borax crystals
are taken out with chisels, after the liquor has been drawn off, and the
whole has become cold.
One hundred parts of the purest acid, usually extracted from the lakes
of Tuscany, contain only fifty parts of the real boracic acid, and yield
no more, at the utmost, than 140 or 150 of good borax.
Dry borax acts on the metallic oxides at a high temperature, in a very
remarkable manner, melting and vitrifying them into beautiful coloured
glasses. On this account it is a most useful reagent for the blowpipe.
Oxide of chrome tinges it of an emerald green; oxide of cobalt, an
intense blue; oxide of copper, a pale green; oxide of tin, opal; oxide
of iron, bottle green and yellow; oxide of manganese, violet; oxide of
nickel, pale emerald green. The white oxides impart no colour to it by
themselves. In the fusion of metals borax protects their surface from
oxidizement, and even dissolves away any oxides formed upon them; by
which twofold agency it becomes an excellent flux, invaluable to the
goldsmith in soldering the precious metals, and to the brazier in
soldering copper and iron.
Borax absorbs muriatic and sulphurous acid gases, but no others, whereby
it becomes, in this respect, a useful means of analysis.
The strength or purity of borax may be tested by the quantity of
sulphuric acid requisite to neutralize a given weight of it, as
indicated by tincture of litmus.
When mixed with shell-lac in the proportion of one part to five, borax
renders that resinous body soluble in water, and forms with it a species
of varnish.
Boracic acid is a compound of 31·19 of boron and 68·81 oxygen, in 100
parts. Its prime equivalent referred to oxygen 100, is 871·96.
The following process for refining the native Indian borax or tincal,
has been published by MM. Robiquet and Marchand:--
It is put into large tubs, covered with water for 3 or 4 inches above
its surface, and stirred through it several times during six hours. For
400 pounds of the tincal there must now be added one pound of quicklime
diffused through two quarts of water. Next day the whole is thrown upon
a sieve, to drain off the water with the impurities, consisting, in some
measure, of the fatty matter combined with the lime, as an insoluble
soap. The borax, so far purified, is to be dissolved in 2-1/2 times its
weight of boiling water, and eight pounds of muriate of lime are to be
added for the above quantity of borax. The liquor is now filtered,
evaporated to the density of 18° or 20° B. (1·14 to 1·16 sp. grav.), and
set to crystallize in vessels shaped like inverted pyramids, and lined
with lead. At the end of a few days, the crystallization being
completed, the mother waters are drawn off, the crystals are detached
and dried. The loss of weight in this operation is about 20 per cent.
The quantity of borax imported into the United Kingdom in 1835 was
335,224 pounds; whereof 122,022 pounds were exported. The duty is 10_s._
upon the refined, and 4_s._ unrefined.
BOOKBINDING, is the art of sewing together the sheets of a book; and
securing them with a back and side boards. Binding is distinguished from
stitching, which is merely sewing the leaves without bands or backs; and
from half-binding, which consists in securing the back only with
leather, the pasteboard sides being covered with blue or marble paper;
whereas in binding, both the back and sides are covered with leather.
Bookbinding, according to the present mode, is performed in the
following manner:--The sheets are first folded into a certain number of
leaves, according to the form in which the book is to appear; viz. two
leaves for folios, four for quartos, eight for octavos, twelve for
duodecimos, &c. This is done with a slip of ivory or boxwood, called a
folding stick; and in the arrangement of the sheets the workmen are
directed by the catch-words and signatures at the bottom of the pages.
When the leaves are thus folded and arranged in proper order, they are
usually beaten upon a stone with a heavy hammer, to make them solid and
smooth, and are then condensed in a press. After this preparation they
are sewed in a sewing press, upon cords or packthreads called bands,
which are kept at a proper distance from each other, by drawing a thread
through the middle of each sheet, and turning it round each band,
beginning with the first and proceeding to the last. The number of bands
is generally six for folios, and five for quartos, or any smaller size.
The backs are now glued, and the ends of the bands are opened, and
scraped with a knife, that they may be more conveniently fixed to the
pasteboard sides; after which the back is turned with a hammer, the book
being fixed in a press between boards, called backing boards, in order
to make a groove for admitting the pasteboard sides. When these sides
are applied, holes are made in them for drawing the bands through, the
superfluous ends are cut off, and the parts are hammered smooth. The
book is next pressed for cutting; which is done by a particular machine
called the plough, to which is attached a knife. See the figures and
descriptions _infra_. It is then put into a press called the cutting
press, betwixt two boards, one of which lies even with the press, for
the knife to run upon; and the other above for the knife to cut against.
After this the pasteboards are cut square with a pair of iron shears;
and last of all, the colours are sprinkled on the edges of the leaves,
with a brush made of hog’s bristles; the brush being held in the one
hand, and the hair moved with the other.
Different kinds of binding are distinguished by different names, such as
law binding, marble binding, French binding, Dutch binding, &c. In Dutch
binding, the backs are vellum. In French binding a slip of parchment is
applied over the back between each band, and the ends are pasted upon
the inside of each pasteboard. This indorsing, as it is called, is
peculiar to the French binders; who are enjoined, by special
_ordonnance_, to back their books with parchment. The parchment is
applied in the press, after the back has been grated to make the paste
take hold. The Italians still bind in a coarse thick paper, and this
they call binding _alla rustica_. It is extremely inconvenient, as it is
liable to wear without particular care.
A patent was obtained in 1799 by Messrs. John and Joseph Williams,
stationers in London, for an improved method of binding books of every
description. The improvement consists of a back, in any curved form,
turned a little at the edges, and made of iron, steel, copper, brass,
tin, or of ivory, bone, wood, vellum, or, in short, any material of
sufficient firmness. This back is put on the book before it is bound, so
as just to cover without pressing the edges; and the advantage of it is
that it prevents the book, when opened, from spreading on either side,
and causes it to rise in any part to nearly a level surface. In this
method of binding the sheets are prepared in the usual manner, then
sewed on vellum slips, glued, cut, clothed, and boarded, or half
boarded; the firm back is then fastened to the sides by vellum drawn
through holes, or secured by inclosing it in vellum or ferret wrappers,
or other materials pasted down upon the boards, or drawn through them.
A patent was likewise obtained in 1800 by Mr. Ebenezer Palmer, a London
stationer, for an improved way of binding books, particularly merchants’
account-books. This improvement has been described as follows:--let
several small bars of metal be provided about the thickness of a
shilling or more, according to the size and thickness of the book; the
length of each bar being from half an inch to several inches, in
proportion to the strength required in the back of the book. At each end
of every bar let a pivot be made of different lengths, to correspond to
the thickness of two links which they are to receive. Each link must be
made in an oval form, and contain two holes proportioned to the size of
the pivots, these links to be the same metal as the hinge, and each of
them nearly equal in length to the width of two bars. The links are then
to be riveted on the pivots, each pivot receiving two of them, and thus
holding the hinge together, on the principle of a link-chain or hinge.
There must be two holes or more of different sizes, as may be required,
on each bar of the hinge or chain; by means of these holes each section
of the book is strongly fastened to the hinge which operates with the
back of the book, when bound, in such a manner as to make the different
sections parallel with each other, and thus admit writing without
inconvenience on the ruled lines, close to the back.
The leather used in covering books is prepared and applied as follows:
being first moistened in water, it is cut to the size of the book, and
the thickness of the edge is paired off on a marble stone. It is next
smeared over with paste made of wheat flour, stretched over the
pasteboard on the outside, and doubled over the edges within. The book
is then corded, that is, bound firmly betwixt two boards, to make the
cover stick strongly to the pasteboard and the back; on the exact
performance of which the neatness of the book in a great measure
depends. The back is then warmed at the fire to soften the glue, and the
leather is rubbed down with a bodkin or folding stick, to set and fix it
close to the back of the book. It is now set to dry, and when dry the
boards are removed; the book is then washed or sprinkled over with a
little paste and water, the edges and squares blacked with ink, and then
sprinkled fine with a brush, by striking it against the hand or a stick;
or with large spots, by being mixed with solution of green vitriol,
which is called marbling. Two blank leaves are then pasted down to the
cover, and the leaves, when dry, are burnished in the press, and the
cover rolled on the edges. The cover is now glazed twice with the white
of an egg, filleted, and last of all, polished, by passing a hot iron
over the glazed colour.
The employment in book binding of a rolling press for smoothing and
condensing the leaves, instead of the hammering which books have usually
received, is an improvement introduced several years ago into the trade
by Mr. W. Burn. His press consists of two iron cylinders about a foot in
diameter, adjustable in the usual way, by means of a screw, and put in
motion by the power of one man or of two, if need be, applied to one or
two winch-handles. In front of the press sits a boy who gathers the
sheets into packets, by placing two, three, or four upon a piece of tin
plate of the same size, and covering them with another piece of tin
plate, and thus proceeding by alternating tin plates and bundles of
sheets till a sufficient quantity have been put together, which will
depend on the stiffness and thickness of the paper. The packet is then
passed between the rollers and received by the man who turns the winch,
and who has time to lay the sheets on one side, and to hand over the tin
plates by the time that the boy has prepared a second packet. A minion
bible may be passed through the press in one minute, whereas the time
necessary to beat it would be twenty minutes. It is not, however, merely
a saving of time that is gained by the use of the rolling press; the
paper is made smoother than it would have been by beating, and the
compression is so much greater, that a rolled book will be reduced to
about five-sixths of the thickness of the same book if beaten. A shelf,
therefore, that will hold fifty books bound in the usual way would hold
nearly sixty of those bound in this manner, a circumstance of no small
importance, when it is considered how large a space even a moderate
library occupies, and that book-cases are an expensive article of
furniture. The rolling press is now substituted for the hammer by
several considerable bookbinders.
[Illustration: 141 142]
_Fig._ 141. represents the sewing press, as it stands upon the table,
before which the bookbinder sits. _Fig._ 142. is a ground plan without
the parts _a_ and _n_ in the former figure. A is the base-board,
supported upon the cross bars _m n_, marked with dotted lines in _fig._
142. Upon the screw rods _r r_ _fig._ 141. the nuts _t d_ serve to fix
the flat upper bar _n_, at any desired distance from the base. That bar
has a slit along its middle, through which the hooks below _z z_ pass
down for receiving the ends of the sewing cords _p p_, fixed at _y y_,
and stretched by the thumb-screws _z z_. The bar _y y_ is let into an
oblong space cut out of the front edge of the base board and fixed there
by a movable pin _a_, and a fixed pin at its other end round which it
turns.
[Illustration: 143]
_Fig._ 143. is the bookbinder’s cutting press, which is set upright upon
a sort of chest for the reception of the paper parings; and consists of
three sides, being open above and to the left hand of the workman. The
pressbar, or beam _a_, has two holes _n n_ upon its under surface, for
securing it to two pegs standing on the top of the chest. The screw rods
_t t_ pass through two tapped holes in the bar, marked with _b c_ at its
upper end; their heads _r r_ being held by the shoulders _o o_. The
heads are pierced with holes into which lever pins are thrust for
screwing the rods hard up. The heavy beam _a_ remains immovable, while
the parallel bar with the book is brought home towards it by the two
screws. The two rulers _s s_ serve as guides to preserve the motions
truly parallel; and the two parallel lath bars _b c_ guide between them
the end bar _e_, of the plough, whose knife is shown at _i_, with its
clamping screw _z_.
[Illustration: 144 145]
Mr. Oldham, printing engineer of the Bank of England, distinguished for
mechanical ingenuity, has contrived a convenient machine for cutting the
edges of books, banknotes, &c. either truly square or polygonal, with
mathematical precision. _Fig._ 144. represents an end elevation of the
machine. _Fig._ 145. a side view of the same, the letters of reference
indicating the same parts of the machine in each of the figures.
[Illustration: 146 147]
_a_, is the top cross bar with rectangular grooves _b b_; _c c_, are
side posts; _d d_, cross feet to the same, with strengthening brackets;
_e e_, a square box, in which the press stands, for holding waste
cuttings. _Fig._ 146. is a cross section of the upright posts, _c c_,
taken horizontally. There are rectangular grooves in the upright posts,
for the projecting ends of the cast iron cross bracket _f_, to slide up
and down in. In the middle of the under-side of this piece _f_, there is
a boss, within which is a round recess, to receive the top of the screw
_g_, which works in the cast iron cross piece _h_, similarly made with
the former, but bolted firmly to the posts _c c_. Upon the screw _g_
there is a circular handle or ring _i_, for partially turning the screw,
and immediately over it cross holes for tightening the press by means of
a lever bar. Upon the cross piece _f_, is bolted the board _j_, and upon
each end of this board is made fast the rabbetted pieces _k k_, for
another board _l_, to slide in. Across the middle of this board, and
parallel to the pieces _k k_, the tongue piece _m_, is made fast, which
fits into a groove in the bottom of board _l_. A horizontal
representation of this is seen at _fig._ 147. and immediately under this
view is also seen an end view of _l_, and _f_, connected together, and a
side view of _f_ by itself. In the middle of the board _l_, is a pin
for a circular board _n_, to turn upon, and upon this latter board is
placed the “material to be cut,” with a saving piece between it, and the
circular piece which is to be divided upon its edge into any number of
parts required, with a stationary index on the board _l_, to point to
each.
It will now be understood that the “material to be cut,” may be turned
round upon the centre pin of the board _n_, and also that both it and
the board can be shifted backward and forward under the top cross piece
_a_, and between the side slide slips _k k_, the surfaces of which
should also be divided into inches and tenths.
The plough, _fig._ 148., shown in several positions, is made to receive
two knives or cutters as the “material to be cut” may require, and which
are situated in the plough as I now describe. The plough is composed of
three principal parts, namely, the top, and its two sides. The top _o_,
is made the breadth of the cross piece _a_, and with a handle made fast
thereon. The sides _p p_, are bolted thereto, with bolts and nuts
through corresponding holes in the top and sides. The figures below give
inside views, and cross sections of the details of the manner in which
the cutters and adjustments are mounted. A groove is cut down each cheek
or side, in which are placed screws that are held at top and bottom from
moving up and down, but by turning they cause the nuts upon them to do
so; they are shown at _q q_. These nuts have each a pin projecting
inwards, that go into plain holes made in the top ends of cutters _r r_.
The 148th. and following figs. are 1/4 in scale.
[Illustration: 148 149 150 151 152 153 154]
The cutters, and the work for causing them to go up and down, are sunk
into the cheeks, so as to be quite level with their inner surfaces.
_Fig._ 149. shows one of those screws apart, how fixed, and with
moveable nut and projecting pin. The top of each screw terminates with a
round split down, and above it a pinion wheel and boss thereon, also
similarly split. This pinion fits upon the split pin. Above, there is
cross section of a hollow coupling cap with steel tongue across, that
fits into both the cuts of the screw pin and pinion boss, so that when
lowered upon each other, they must all turn together. In the middle and
on the top of the upper piece _o_, the larger wheel _s_, runs loose upon
its centre, and works into the two pinion-wheels _t t_. The wheel _s_
has a fly-nut with wings mounted upon it.
It will now be seen, when the plough is in its place as at _fig._ 150.,
that if it be pushed to and fro by the right hand, and the nut
occasionally turned by the left, the knives or cutters will be protruded
downwards at the same time, and these either will or will not advance as
the coupling caps _u u_ are on or off. The ribs _v v_, run in the
grooves _b b_, _fig._ 144., and keep the cutters to their duty, working
steadily. The top cross bar _a_, is the exact breadth of a bank-note, by
which means both knives are made to cut at the same time. The paper is
cut uniformly to one length, and accurately square.
By the use of this machine, the air-pump paper-wetting apparatus, and
appendant press, the paper of 45,000 notes is fully prepared in one hour
and a half by one person, and may then be printed. It is not so much
injured by this process as by the ordinary method of clipping by hand,
soaking it, &c., which more or less opens and weakens the fabric,
especially of bank-note paper.
One of the greatest improvements ever made in the art of bookbinding is,
apparently, that for which Mr. William Hancock has very recently
obtained a patent. After folding the sheets in double leaves, he places
them vertically, with the edges forming the back of the book downwards
in a concave mould, of such rounded or semi-cylindrical shape as the
back of the book is intended to have. The mould for this purpose
consists of two parallel upright boards, set apart upon a cradle frame,
each having a portion or portions cut out vertically, somewhat deeper
than the breadth of the book, but of a width nearly equal to its
thickness before it is pressed. One of these upright boards may be
slidden nearer to or farther from its fellow, by means of a guide bar,
attached to the sole of the cradle. Thus the distance between the
concave bed of the two vertical slots in which the book rests, may be
varied according to the length of the leaves. In all cases about
one-fourth of the length of the book at each end projects beyond the
board, so that one half rests between the two boards. Two or three
packthreads are now bound round the leaves thus arranged, from top to
bottom of the page in different lines, in order to preserve the form
given to the back of the mould in which it lay. The book is next
subjected to the action of the press. The back, which is left projecting
_very slightly_ in front, is then smeared carefully by the fingers with
a solution of caoutchouc, whereby each paper-edge receives a small
portion of the cement. In a few hours it is sufficiently dry to take
another coat of a somewhat stronger caoutchouc solution. In 48 hours, 4
applications of the caoutchouc may be made and dried. The back and the
adjoining part of the sides are next covered with the usual band or
fillet of cloth, glued on with caoutchouc; after which the book is ready
to have the boards attached, and to be covered with leather or parchment
as may be desired.
We thus see that Mr. Hancock dispenses entirely with the operations of
stitching, sewing, sawing-in, hammering the back, or the use of paste
and glue. Instead of leaves attached by thread stitches at 2 or 3
points, we have them agglutinated securely along their whole length.
Books bound in this way open so perfectly flat upon a table without
strain or resilience, that they are equally comfortable to the student,
the musician, and the merchant. The caoutchouc cement moreover being
repulsive to insects, and not affected by humidity, gives this mode of
binding a great superiority over the old method with paste or glue,
which attracted the ravages of the moth, and in damp situations allowed
the book to fall to pieces. For engravings, atlasses, and ledgers, this
binding is admirably adapted, because it allows the pages to be
displayed most freely, without the risk of dislocating the volume; but
for security, 3 or 4 stitches should be made. The leaves of music-books
bound with caoutchouc, when turned over, lie flat at their whole extent,
as if in loose sheets, and do not torment the musician like the leaves
of the ordinary books, which are so ready to spring back again.
Manuscripts and collections of letters which happen to have little or no
margin left at the back for stitching them by, may be bound by Mr.
Hancock’s plan without the least encroachment upon the writing. The
thickest ledgers thus bound, open as easily as paper in quire, and may
be written on up to the innermost margin of the book without the least
inconvenience.
Having inspected various specimens of Mr. Hancock’s workmanship, I
willingly bear testimony to the truth of the preceding statement. See
CLOTH BINDING.
[Illustration: 155]
BOTTLE MANUFACTURE. The following mechanism for moulding bottles, forms
the subject of a patent obtained by Henry Rickets of Bristol in 1822.
_Fig._ 155. is a section of the apparatus, consisting of a square frame,
_a a_, of iron or wood; this is fixed in a pit formed in the floor; _b
b_ is the base of the frame, with an aperture for knocking up the bottom
of the bottle; _c c_ are four legs secured to the frame-floor _b_, upon
which the mould is supported. The platform or stand of the mould _d d_
has an opening in its centre for the introduction of the bottom of the
mould, which is raised against the bottom of the bottle by the knocker
up; _e e_ are the sides of the mould; and _f f_ is the top of the mould
in two pieces, turning over upon the joints at _g g_, so as to form the
neck of the bottle; _h h_ are levers or arms for raising and depressing
the top pieces; _i i_ is a horizontal shaft or axle, turning in bearings
at each end, from which shaft two levers, _k k_, extend; these levers
are connected by upright rods, _l l_, to the levers or arms, _h h_, of
the top pieces _f f_.
The weight of the arms _h h_, and rods _l l_, will, by their gravity,
cause the top pieces to open, as shown by the dotted lines; in this
situation of the mould, the melted glass is to be introduced by a tube
as usual. The workman then steps with one foot upon the knob _m_, which
forces down the rod _n_, and by means of a short lever _o_, extending
from the shaft _i_, forces down the top pieces _f_, and closes the
mould, as seen in the figure; the glass is then made to extend itself to
the shape of the mould, by blowing as usual, so as to form the bottle,
and the workman at this time putting his other foot upon the knob _p_,
depresses the rod _q_, and hence raises the bottom of the mould by means
of the knocker-up, _r_, so as to form the bottom of the bottle.
At the bottom of the mould a ring is introduced of any required
thickness, for the purpose of regulating the capacity of the bottle;
upon which ring it is proposed to raise letters and figures, as a mould
to imprint the maker’s name and the size of the bottle. These moulds can
be removed and changed at pleasure. Under the knob _p_, a collar or
washer is to be introduced, of any required thickness, to regulate the
knocking up of the bottom, by which a perfect symmetry of form is
presented. In order to make bottles of different sizes or forms, the
mould is intended to be removed, and its place supplied by another mould
of different dimensions and figure; the lower parts of all the moulds
being made to fit the same frame. Such a mould ought to be prescribed by
legislative enactment, with an excise stamp to define the capacity of
every bottle, and thereby put an end to the interminable frauds
committed in the measure of wine and all other liquors sold by the
bottle.
BOUGIE. A smooth, flexible, elastic, slender cylinder, introduced into
the urethra, rectum, or œsophagus, for opening or dilating it, in cases
of stricture and other diseases. The invention of this instrument is
claimed by Aldereto, a Portuguese physician, but its form and uses were
first described by his pupil Amatus, in the year 1554. Some are solid,
and some hollow; some corrosive, and some mollifying. They generally owe
their elasticity to linseed oil, inspissated by long boiling, and
rendered drying by litharge. This viscid matter is spread upon a very
fine cord or tubular web of cotton, flax, or silk, which is rolled upon
a slab when it becomes nearly solid by drying, and is finally polished
in the same way.
Pickel, a French professor of medicine, published the following recipe
for the composition of bougies. Take 3 parts of boiled linseed oil, one
part of amber, and one of oil of turpentine; melt and mix these
ingredients well together, and spread the compound at three successive
intervals upon a silk cord or web. Place the pieces so coated in a stove
heated to 150° F.; leave them in it for 12 hours, adding 15 or 16 fresh
layers in succession, till the instruments have acquired the proper
size. Polish them first with pumice-stone, and finally smooth with
tripoli and oil. This process is the one still employed in Paris, with
some slight modifications; the chief of which is dissolving in the oil
one twentieth of its weight of caoutchouc to render the substance more
solid. For this purpose the caoutchouc must be cut into slender shreds,
and added gradually to the hot oil. The silk tissue must be fine and
open, to admit of the composition entering freely among its filaments.
Each successive layer ought to be dried first in a stove, and then in
the open air, before another is applied. This process takes two months
for its completion, in forming the best bougies called _elastic_; which
ought to bear twisting round the finger without cracking or scaling, and
extension without giving way, but retracting when let go. When the
bougies are to be hollow, a mandril of iron wire, properly bent with a
ring at one end, is introduced into the axis of the silk tissue. Some
bougies are made with a hollow axis of tin foil rolled into a slender
tube. Bougies are also made entirely of caoutchouc, by the intervention
of a solution of this substance in sulphuric ether, a menstruum
sufficiently cheap in France, on account of the low duty upon alcohol.
There are medicated bougies, the composition of which belongs to
surgical pharmacy. The manufacture of these instruments of various kinds
forms a separate and not inconsiderable branch of industry at Paris. MM.
Feburger and Lamotte are eminent in this line.
BRACES. (_Bretelles_, Fr. _Hosenträger_, Germ.) Narrow fillets or bands
of leather or textile fabric, which pass over the shoulders, and are
attached behind and before to the waistbands of pantaloons and trowsers,
in the act of wearing them, for supporting their weight, and _bracing_
them up to the body. It is a useful modern invention, superseding the
necessity of girding the belly with a tight girdle, as in former times.
[Illustration: 156 157]
BRAIDING MACHINE. (_Machine à lacets_, Fr.; _Bortenwerkerstuhl_, Germ.)
This being employed, not only to manufacture stay-laces, braid, and
upholsterer’s cord, but to cover the threads of caoutchouc for weaving
brace-bands, deserves a description in this work. Three threads at least
are required to make such a knitted lace, but 11, 13, or 17, and even 29
threads are often employed, the first three numbers being preferred.
They are made by means of a frame of a very ingenious construction,
which moves by a continuous rotation. We shall describe a frame with 13
threads, from which the structure of the others may be readily
conceived. The basis of the machine consists of four strong wooden
uprights, A, _fig._ 156, 157, 158., occupying the four angles of a
rectangle, of which one side is 14 inches long, the other 18 inches, and
the height of the rectangle about 40 inches. _Fig._ 156. is a section in
a horizontal plane, passing through the line _a b_ of _fig._ 157. which
is a vertical section in a plane passing through the centre of the
machine C, according to the line _c d_, _fig._ 156. The side X is
supposed to be the front of the frame; and the opposite side, Y, the
back. B, six spindles or skewers, numbered, from 1 to 6, placed in a
vertical position upon the circumference of a circle, whose centre
coincides with that of the machine at the point C. These six spindles
are composed, 1. Of so many iron shafts or axes D, supported in brass
collets E, (_fig._ 157.) and extended downwards within 6 inches of the
ground, where they rest in brass steps fixed upon a horizontal beam. 2.
Wooden heads, made of horn-beam or nut-tree, placed, the first upon the
upper end of each spindle, opposite the cut-out beam F, and the second
opposite the second beam G. 3. Wooden-toothed wheels, H, reciprocally
working together, placed between the beam G, and the collet-beam E. The
toothed wheels and the lower heads for each spindle are in one piece.
The heads and shafts of the spindles No. 1. and 6., are one fifth
stronger than those of the other spindles; their heads have five
semi-circular grooves, and wheels of 60 teeth, while the heads of the
others have only four grooves, and wheels of 48 teeth; so that the
number of the grooves in the six spindles is 26, one half of which is
occupied with the stems of the puppets I, which carry the 13 threads
from No. 1. to 13. The toothed wheels, which give all the spindles a
simultaneous movement, but in different directions, are so disposed as
to bring their grooves opposite to each other in the course of rotation.
K, the middle winglet, triple at bottom and quintuple at top, which
serves to guide the puppets in the direction they ought to pursue.
L, three winglets, single at top and bottom, placed exteriorly, which
serve a like purpose.
M, two winglets, triple at bottom and single at top, placed likewise
exteriorly, and which serve the same purposes as the preceding; _m_, are
iron pins inserted in the cut-out beam G, which serve as stops or limits
to the oscillations of the exterior winglets.
Now, if by any moving power (a man can drive a pair) rotation be
impressed upon the large spindle No. 1., in the direction of the arrow,
all the other spindles will necessarily pursue the rotatory movement
indicated by the respective arrows. In this case, the 13 puppets working
in the grooves of the heads of the spindles will be carried round
simultaneously, and will proceed each in its turn, from one extremity of
the machine to the opposite point, crossing those which have a
retrograde movement. The 13 threads united at the point N, situated
above the centre of the machine, will form at that point the braid,
which after having passed over the pulley _o_, comes between the two
rollers P Q, and is squeezed together, as in a flatting-mill, where the
braid is calendered at the same time that it is delivered. It is obvious
that the roller P, receives its motion from the toothed wheel of the
spindle No. 3., and from the intermediate wheels R, S, T, as well as
from the endless screw Z, which drives at proper speed the wheel W,
fixed upon the shaft of the roller P.
The braid is denser in proportion as the point N is less elevated above
the tops of the puppets; but in this case, the eccentric motion of these
puppets is much more sensible in reference to that point, towards which
all the threads converge, than when it is elevated. The threads which
must be always kept equally stretched by means of a weight, as we shall
presently see, are considerably strained by the traction, occasioned by
the constantly eccentric movement of the puppets. From this cause,
braiding machines must be worked at a moderate velocity. In general, for
fine work, 30 turns of the large spindle per minute are the utmost that
can safely be made.
[Illustration: 158]
The puppet or spindle of this machine, being the most important piece, I
have represented it in section, upon a scale one fourth of its actual
size, _fig._ 158. It is formed of a tube, _a_, of strong sheet iron well
brazed; _b_ is a disc, likewise of sheet iron, from which a narrow
fillet, _c_, rises vertically as high as the tube, where both are
pierced with holes, _d e_, through which the thread _f_ is passed, as it
comes from the bobbin, _g_, which turns freely upon the tube _a_. The
top of this bobbin is conical and toothed. A small catch or detent, _h_,
moveable in a vertical direction round _i_, falls by its own weight into
the teeth of the crown of the bobbin, in which case this cannot revolve;
but when the detent is raised so far as to disengage the teeth, and at
the same time to pull the thread, the bobbin turns, and lets out thread
till the detent falls back into these same teeth.
A skewer of iron wire, _k_, is loaded with a small weight, _l_, melted
upon it. The top of this skewer has an eye in it, and the bottom is
recurved as is shown in _fig._ 158., so that supposing the thread comes
to break, this skewer falls into the actual position in the figure,
where we see its lower end extending beyond the tube _a_, by about 1/4
of an inch; but as long as the thread is unbroken, the skewer _k_, which
serves to keep it always tense, during the eccentric movement of the
puppet, does not pass out below the tube.
This disposition has naturally furnished the means of causing the
machine to stop, whenever one of the threads breaks. This inferior
protrusion of the skewer pushes in its progress a detent, which
instantly causes the band to slide from the driving pulley to the loose
pulley. Thus the machine cannot operate unless all the threads be
entire. It is the business of the operative, who has 3 or 4 under her
charge, to mend the threads as they break, and to substitute full
bobbins for empty ones, whenever the machine is stopped.
The braiding frame, though it does not move quickly, makes a great deal
of noise, and would make still more, were the toothed wheels made of
metal instead of wood. For them to act well, they should be made with
the greatest precision, by means of appropriate tools for forming the
teeth of the wheels, and the other peculiar parts.
BRAN. (_Son_, Fr.; _Kleie_, Germ.) The husky portion of ground wheat,
separated by the boulter from the flour. It is advantageously employed
by the calico printers, in the clearing process, in which, by boiling in
bran-water, the colouring matters adhering to the non-mordanted parts of
maddered goods, as well as the dun matters which cloud the mordanted
portions, are removed. A valuable series of researches concerning the
operation of bran in such cases was made a few years ago by that
distinguished chemist and calico printer, M. Daniel Kœchlin-Schouch, and
published in the ninth number of the Bulletin de la Société Industrielle
de Mulhausen. Nine sets of experiments are recorded, which justified the
following conclusions.
1. The dose of two bushels of bran for 10 pieces of calico is the best,
the ebullition being kept up for an hour. A boil for the same time in
pure water had no effect in clearing either the grounds or the figures.
2. Fifteen minutes boiling are sufficient when the principal object is
to clear white grounds, but in certain cases thirty minutes are
requisite to brighten the dyed parts. If, by increasing the charge of
bran, the time of the ebullition could be shortened, it would be in some
places, as Alsace, an economy; because for the passage of ten pieces
through a copper or vat heated with steam, 1 cwt. of coal is consumed in
fuel which costs from 2-1/2 to 3 francs, while two bushels of bran are
to be bought for one franc.
3. By increasing the quantity of water from 12 to 24 hectolitres with
two bushels of bran, the clearing effect upon the ten pieces was
impaired. It is therefore advantageous not to use too much water.
4. Many experiments concur to prove that flour is altogether useless for
the clearing boil, and that finer bran is inferior for this purpose to
the coarser.
5. The white ground of the calicoes boiled with wheat bran, are
distinguishable by their superior brightness from that of those boiled
with rye bran, and especially with barley bran; the latter having hardly
any effect.
6. There is no advantage in adding soap to the bran boil; though a
little potash or soda may be properly introduced when the water is
calcareous.
7. The pellicle of the bran is the most powerful part, the flour and the
starch are of no use in clearing goods, but the mucilage which forms one
third of the weight of the bran has considerable efficacy, and seems to
act in the following way. In proportion as the mucilaginous substance
dissolves the colouring and tawny matters upon the cloth, the husky
surface attracts and fixes upon itself the greater part of them.
Accordingly, when used bran is digested in a weak alkaline bath, it
gives up the colour which it had absorbed from the cloth.
The following chemical examination of bran is interesting. A pound of it
was boiled at successive times with water, the decoctions being
filtered, let fall in cooling a greyish deposit, which was separated by
decantation. The clear liquor afforded by evaporation to dryness four
ounces of a brownish, brittle matter, composed chiefly of mucilage, a
little gluten, and starch. The gray deposit of the above filtered liquor
amounted to half an ounce. Nine ounces of the cortical portion of the
bran were obtained. The loss amounted to 2-1/2 ounces, being in some
measure the hygrometric water of the bran itself.
When boiled with distilled water, goods are cleared pretty well without
bran. Certain delicate dyes must be boiled only a few minutes in a
strong decoction of bran previously made.
BRANDY. The name given in this country to ardent spirits distilled from
wine, and possessed of a peculiar taste and flavour, due to a minute
portion of a peculiar volatile oil. Each variety of alcohol has an aroma
characteristic of the fermented substance from which it is procured;
whether it be the grape, cherries, sugar-cane, rice, corn, or potatoes;
and it may be distinguished even as procured from different growths of
the vine. The brandies of Languedoc, Bordeaux, Armagnac, Cognac, Aunis,
Saintonge, Rochelle, Orleans, Barcelona, Naples, &c. being each readily
recognisable by an experienced dealer.
Aubergier showed, by experiments, that the disagreeable taste of the
spirits distilled from the _marc_ of the grape is owing to an essential
oil contained in the skin of the grape; and found that the oil, when
insulated, is so energetic that a few drops are sufficient to taint a
pipe of 600 litres of fine-flavoured spirit.
The most celebrated of the French brandies, those of Cognac and
Armagnac, are slightly rectified to only from 0·935 to 0·922; they
contain more than half their weight of water, and come over therefore
highly charged with the fragrant essential oil of the husk of the grape.
When, to save expense of carriage, the spirit is rectified to a much
higher degree, the dealer, on receiving it at Paris, reduces it to the
market proof by the addition of a little highly-flavoured weak brandy
and water; but he cannot in this way produce so finely-flavoured a
spirit, as the weaker product of distillation of the Cognac wine. If the
best Cognac brandy be carefully distilled at a low heat, and the strong
spirit be diluted with water, it will be found to have suffered much in
its flavour.
Genuine French brandy evinces an acid reaction with litmus paper, owing
to a minute portion of vinegar; it contains besides some acetic ether,
and, when long kept in oak casks, a little astringent matter. The
following formula may be proposed for converting a silent or flavourless
corn spirit, into a factitious brandy. Dilute the pure alcohol to the
proof pitch, add to every hundred pounds weight of it from half a pound
to a pound of argol (crude winestone) dissolved in water, a little
acetic ether, and French-wine vinegar, some bruised French plums, and
flavour-stuff from Cognac; then distil the mixture with a gentle fire,
in an alembic furnished with an agitator.
The spirit which comes over may be coloured with nicely burned sugar
(caramel) to the desired tint, and roughened in taste with a few drops
of tincture of catechu or oak-bark.
The above recipe will afford a spirit free from the deleterious drugs
too often used to disguise and increase the intoxicating power of
British brandies; one which may be reckoned as wholesome as alcohol, in
any shape, can ever be.
BRASS. (_Laiton_, _cuivre jaune_, Fr.; _Messing_, Germ.) An alloy of
copper and zinc. It was formerly manufactured by cementing granulated
copper, called _bean-shot_, or copper clippings, with calcined calamine
(native carbonate of zinc) and charcoal, in a crucible, and exposing
them to bright ignition. Three parts of copper were used for three of
calamine and two of charcoal. The zinc reduced to the metallic state by
the agency of the charcoal, combined with the copper, into an alloy
which formed, on cooling, a lump at the bottom of the crucible. Several
of these, being remelted and cast into moulds, constituted ingots of
brass for the market. James Emerson obtained a patent, in 1781, for
making brass by the direct fusion of its two metallic elements, and it
is now usually manufactured in this way.
It appears that the best proportion of the constituents to form fine
brass is one prime equivalent of copper = 63-1/2 + one of zinc = 32·3;
or very nearly 2 parts of copper to 1 of zinc. The bright gold coloured
alloy, called Prince’s, or Prince Rupert’s metal, in this country,
consists apparently of two primes of zinc to one of copper, or of nearly
equal parts of each. Brass, or hard solder, consists of two parts of
brass and one of zinc melted together, to which a little tin is
occasionally added; but when the solder must be very strong, as for
brass tubes that are to undergo drawing, two thirds of a part of zinc
are used for two parts of brass. Mosaic gold, according to the
specification of Parker and Hamilton’s patent consists of 100 parts of
copper, and from 52 to 55 of zinc; which is no atomic proportion. Bath
metal is said to consist of 32 parts of brass and 9 parts of zinc.
The button manufacturers of Birmingham make their _platin_ with 8 parts
of brass and 5 of zinc; but their cheap buttons with an alloy of copper,
tin, zinc, and lead.
Red brass, the Tombak of some, (not of the Chinese, for this is white
copper,) consists of more copper and less zinc than go to the
composition of brass; being from 2-1/2 to 8 or 10 of the former to 1 of
the latter. At the famous brass works of Hegermühl, to be presently
described, 11 parts of copper are alloyed with 2 of zinc into a red
brass, from which plates are made that are afterwards rolled into
sheets. From such an alloy the Dutch foil, as it is called, is
manufactured at Nürnberg; Pinchbeck, Similor, Mannheim gold, are merely
different names of alloy similar to Prince’s metal. The last consists of
3 of copper and 1 of zinc, separately melted, and suddenly incorporated
by stirring.--_Wiegleb._
In the process of alloying two metals of such different fusibilities as
copper and zinc, a considerable waste of the latter metal by the
combustion, to which it is so prone, might be expected; but, in reality,
their mutual affinities seem to prevent the loss, in a great measure, by
the speedy absorption of the zinc into the substance of the copper.
Indeed, copper plates and rods are often _brassed_ externally by
exposure, at a high temperature, to the fumes of zinc, and afterwards
laminated or drawn. The spurious gold wire of Lyons is made from such
rods. Copper vessels may be superficially converted into brass by
boiling them in dilute muriatic acid, containing some winestone and zinc
amalgam.
The first step in making brass is to plunge slips of copper into melted
zinc till an alloy of somewhat difficult fusion be formed, to raise the
heat, and add the remaining proportion of the copper.
The brass of the first fusion is broken to pieces, and melted with a
fresh quantity of zinc, to obtain the finished brass. Each melting takes
about 8 or 9 hours. The metal is now cast into plates, about 40 inches
long by 26 inches broad, and from one third to one half inch thick. The
moulds are, in this case also, slabs of granite mounted in an iron
frame. Granite appears to be preferred to every thing else as a mould,
because it preserves the heat long, and by the asperities of its
surface, it keeps hold of the clay lute applied to secure the joinings.
The cast plates are most usually rolled into sheets. For this purpose
they are cut into ribands of various breadths, commonly about 6-1/2
inches. The cylinders of the brass rolling-press are generally 46 inches
long, and 18 inches in diameter. The ribands are first of all passed
cold through the cylinders; but the brass soon becomes too hard to
laminate. It is then annealed in a furnace, and, after cooling, is
passed afresh through a rolling press. After paring off the chipped
edges, the sheets are laminated two at a time: and if they are to be
made very thin, even eight plates are passed through together. The brass
in these operations must be annealed 7 or 8 times before the sheet
arrives at the required thinness. These successive heatings are very
expensive; and hence they have led the manufacturers to try various
plans of economy. The annealing furnaces are of two forms according to
the size of the sheets of brass. The smaller are about 12 feet long,
with a fire place at each end, and about 13 inches wide. The arch of the
furnace has a cylindrical shape, whose axis is parallel to its small
side. The hearth is horizontal, and is made of bricks set on edge. In
the front of the furnace there is a large door, which is raised by a
lever, or chain, and counterweight, and slides in a frame between two
cheeks of cast iron. This furnace has, in general, no chimney, except a
vent slightly raised above the door, to prevent the workmen being
incommoded by the smoke. Sometimes the arch is perforated with a number
of holes. The sheets of brass are placed above each other, but separated
by parings, to allow the hot air to circulate among them, the lowest
sheet resting upon two bars of cast iron placed lengthwise.
The large furnaces are usually 32 feet long, by 6-1/2 feet wide, in the
body, and 3 feet at the hearth. A grate, 13 inches broad, extends along
each side of the hearth, through its whole length, and is divided from
it by a small wall, 2 or 3 inches high. The vault of the furnace has a
small curvature, and is pierced with 6 or 8 openings, which allow the
smoke to pass off into a low bell-chimney above. At each end of the
furnace there is a cast-iron door, which slides up and down in an iron
frame, and is poised by a counterweight. On the hearth there is a kind
of railway, composed of two iron bars, on the grooves of which the
carriage moves with its loads of sheets of brass.
These sheets, being often 24 feet long, could not be easily moved in and
out of the furnace; but as brass laminates well in the cold state, they
are all introduced and moved out together. With this view, an iron
carriage is framed with four bars, which rest on four wheels. Upon this
carriage, of a length nearly equal to that of the furnace, the sheets
are laid, with brass parings between them. The carriage is then raised
by a crane to a level with the furnace, and entered upon the grooved
bars which lie upon the hearth. That no heat may be lost, two carriages
are provided, the one being ready to put in as the other is taken out;
the furnace is meanwhile uniformly kept hot. This method, however
convenient for moving the sheets in and out, wastes a good deal of fuel
in heating the iron carriage.
The principal places in which brass is manufactured on the great scale
in England, are Bristol, Birmingham, and Holywell, in North Wales.
The French writers affirm, that a brass, containing 2 _per cent._ of
lead, works more freely in the turning lathe, but does not hammer so
well as the mere alloy of copper and zinc.
At the brass manufactory of Hegermühl, upon the Finon canal near
Potsdam, the following are the materials of one charge; 41 pounds of old
brass, 55 pounds refined copper (gahrkupfer) granulated; and 24 pounds
of zinc. This mixture, weighing 120 pounds, is distributed into four
crucibles, and fused in a wind furnace with pitcoal fuel. The waste
varies from 2-1/2 to 4 pounds upon the whole.
[Illustration: 159 160]
_Fig._ 159. represents the furnace as it was formerly worked there with
charcoal; _a_, the laboratory in which the crucibles were placed. It was
walled with fire bricks. The foundations and the filling-in walls were
formed of stone rubbish, as being bad conductors of heat; sand and ashes
may be also used; _b_, cast-iron circular grating plates pierced with
12 holes (see _fig._ 160.), over them a sole of loam, _c_, is beat down,
and perforated with holes corresponding to those in the iron discs; _d_,
the ash-pit; _e_, the _bock_, a draught flue which conducts the air
requisite to the combustion, from a sunk tunnel, in communication with
several melting furnaces. The terrace or crown of the furnace, _f_, lies
on a level with the foundry floor, _h h_, and is shut with a tile of
fire-clay, _g_, which may be moved in any direction by means of hooks
and eyes in its binding iron ring. _Fig._ 161. the tongs for putting in
and taking out the charges, as viewed from above and from the side.
[Illustration: 161 162 163]
_Figs._ 162, 163. represent the furnaces constructed more recently for
the use of pitcoal fuel; _fig._ 162. being an upright section, and
_fig._ 163. the ground plan. In this furnace the crucibles are not
surrounded with the fuel, but they receive the requisite melting heat
from the flame proceeding from the grate upon which it is burned. The
crucibles stand upon 7 binding arches, _a_, which unite in the middle at
the key-stone _b_, _fig._ 163. Between the arches are spaces through
which the flame rises from the grate _c_. _d_ is the fire-door; _e_, a
sliding tile or damper for regulating or shutting off the air-draught;
_f_ an inclined plane, for carrying off the cinders that fall through
the grate, along the draught tunnel _g_, so that the air in entering
below may not be heated by them.
The crucibles are 16 inches deep, 9-1/2 wide at the mouth, 6-1/2 at the
bottom; with a thickness in the sides of 1 inch and 1-1/2 below; they
stand from 40 to 50 meltings. The old brass, which fills their whole
capacity, is first put in and melted down; the crucibles are now taken
out, and are charged with the half of the zinc in pieces of from 1 to 3
cubic inches in size, covered over with coal ashes; then one half of the
copper charge is introduced, again coal-dust; and thus the layers of
zinc and copper are distributed alternately with coal-ashes betwixt
them, till the whole charge gets finally fused. Over all, a thicker
layer of carbonaceous matter is laid, to prevent oxidizement of the
brass. Eight crucibles filled in this way are put into the furnace
between the 11 holes of the grate shelf; and over them two empty
crucibles are laid to be heated for the casting operation. In from 3-1/2
to 4 hours the brass is ready to be poured out. Fifteen English bushels
of coals are consumed in one operation; of which six are used at the
introduction of the crucibles, and four gradually afterwards.